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All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <limits.h> #include <stdarg.h> #include <stdio.h> #include <unistd.h> #include <CommonCrypto/CommonDigest.h> #include <string> #include <unordered_map> #include <unordered_set> #include "StringUtils.h" #include "Trie.hpp" #include "MachOFileAbstraction.hpp" #include "MachOAnalyzer.h" #include "Diagnostics.h" #include "DyldSharedCache.h" #include "CacheBuilder.h" static const bool verbose = false; template <typename P> class StubOptimizer { public: void redirectCallSitesToIslands(); StubOptimizer(int64_t cacheSlide, const std::string& archName, const CacheBuilder::StubOptimizerInfo& image, const std::unordered_map<uint64_t, std::pair<uint64_t, uint8_t*>>& stubsToIslands, Diagnostics& diags); void buildStubMap(const std::unordered_set<std::string>& neverStubEliminate); void optimizeStubs(); void optimizeCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr); const char* dylibID() { return _dylibID; } const uint8_t* exportsTrie() { if ( _dyldInfo != nullptr ) return &_linkeditBias[_dyldInfo->export_off()]; else return &_linkeditBias[_exportTrie->dataoff()]; } uint32_t exportsTrieSize() { if ( _dyldInfo != nullptr ) return _dyldInfo->export_size(); else return _exportTrie->datasize(); } uint32_t _stubCount = 0; uint32_t _stubOptimizedCount = 0; uint32_t _stubsLeftInterposable = 0; uint32_t _branchToStubCount = 0; uint32_t _branchOptimizedToDirectCount = 0; uint32_t _branchToOptimizedStubCount = 0; uint32_t _branchToReUsedOptimizedStubCount = 0; private: typedef std::function<bool(uint8_t callSiteKind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction)> CallSiteHandler; typedef typename P::uint_t pint_t; typedef typename P::E E; void forEachCallSiteToAStub(CallSiteHandler); void optimizeArm64CallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr); void optimizeArm64Stubs(); void redirectArm64CallSitesToIslands(); #if SUPPORT_ARCH_arm64e void optimizeArm64eStubs(); void redirectArm64eCallSitesToIslands(); #endif #if SUPPORT_ARCH_arm64_32 void optimizeArm64_32Stubs(); void redirectArm64_32CallSitesToIslands(); #endif void optimizeArmCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr); void optimizeArmStubs(); uint64_t lazyPointerAddrFromArm64Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr); #if SUPPORT_ARCH_arm64e uint64_t lazyPointerAddrFromArm64eStub(const uint8_t* stubInstructions, uint64_t stubVMAddr); #endif #if SUPPORT_ARCH_arm64_32 uint64_t lazyPointerAddrFromArm64_32Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr); #endif uint32_t lazyPointerAddrFromArmStub(const uint8_t* stubInstructions, uint32_t stubVMAddr); int32_t getDisplacementFromThumbBranch(uint32_t instruction, uint32_t instrAddr); uint32_t setDisplacementInThumbBranch(uint32_t instruction, uint32_t instrAddr, int32_t displacement, bool targetIsThumb); uint32_t cpuSubtype() { return ((dyld3::MachOFile*)_mh)->maskedCpuSubtype(); } struct AddressAndName { pint_t targetVMAddr; const char* targetName; }; typedef std::unordered_map<pint_t, AddressAndName> StubVMAddrToTarget; typedef const std::unordered_map<uint64_t, std::pair<uint64_t, uint8_t*>> StubsToIslands; static const int64_t b128MegLimit = 0x07FFFFFF; static const int64_t b16MegLimit = 0x00FFFFFF; typedef CacheBuilder::DylibSectionCoalescer::OptimizedSection GOTSection; Diagnostics& _diagnostics; macho_header<P>* _mh; const GOTSection* _coalescedGOTs = nullptr; const GOTSection* _coalescedAuthGOTs = nullptr; int64_t _cacheSlide = 0; uint32_t _linkeditSize = 0; uint64_t _linkeditAddr = 0; const uint8_t* _linkeditBias = nullptr; const char* _dylibID = nullptr; const macho_symtab_command<P>* _symTabCmd = nullptr; const macho_dysymtab_command<P>* _dynSymTabCmd = nullptr; const macho_dyld_info_command<P>* _dyldInfo = nullptr; const macho_linkedit_data_command<P>* _exportTrie = nullptr; macho_linkedit_data_command<P>* _splitSegInfoCmd = nullptr; const macho_section<P>* _textSection = nullptr; const macho_section<P>* _stubSection = nullptr; uint32_t _textSectionIndex = 0; uint32_t _stubSectionIndex = 0; pint_t _textSegStartAddr = 0; std::vector<macho_segment_command<P>*> _segCmds; std::unordered_map<pint_t, pint_t> _stubAddrToLPAddr; std::unordered_map<pint_t, pint_t> _lpAddrToTargetAddr; std::unordered_map<pint_t, const char*> _targetAddrToName; std::unordered_set<uint64_t> _stubsToOptimize; StubsToIslands& _stubsToIslands; }; template <typename P> StubOptimizer<P>::StubOptimizer(int64_t cacheSlide, const std::string& archName, const CacheBuilder::StubOptimizerInfo& image, StubsToIslands& stubsToIslands, Diagnostics& diags) : _diagnostics(diags), _mh((macho_header<P>*)image.mh), _coalescedGOTs(image.gots), _coalescedAuthGOTs(image.auth_gots), _cacheSlide(cacheSlide), _dylibID(image.dylibID), _stubsToIslands(stubsToIslands) { const macho_load_command<P>* const cmds = (macho_load_command<P>*)((uint8_t*)_mh + sizeof(macho_header<P>)); const uint32_t cmd_count = _mh->ncmds(); macho_segment_command<P>* segCmd; uint32_t sectionIndex = 0; const macho_load_command<P>* cmd = cmds; for (uint32_t i = 0; i < cmd_count; ++i) { switch (cmd->cmd()) { case LC_SYMTAB: _symTabCmd = (macho_symtab_command<P>*)cmd; break; case LC_DYSYMTAB: _dynSymTabCmd = (macho_dysymtab_command<P>*)cmd; break; case LC_SEGMENT_SPLIT_INFO: _splitSegInfoCmd = (macho_linkedit_data_command<P>*)cmd; break; case LC_DYLD_INFO: case LC_DYLD_INFO_ONLY: _dyldInfo = (macho_dyld_info_command<P>*)cmd; break; case LC_DYLD_EXPORTS_TRIE: _exportTrie = (macho_linkedit_data_command<P>*)cmd; break; case macho_segment_command<P>::CMD: segCmd =( macho_segment_command<P>*)cmd; _segCmds.push_back(segCmd); if ( strcmp(segCmd->segname(), "__LINKEDIT") == 0 ) { _linkeditBias = (uint8_t*)(segCmd->vmaddr() + _cacheSlide - segCmd->fileoff()); _linkeditSize = (uint32_t)segCmd->vmsize(); _linkeditAddr = segCmd->vmaddr(); } else if ( strcmp(segCmd->segname(), "__TEXT") == 0 ) { _textSegStartAddr = (pint_t)segCmd->vmaddr(); const macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)segCmd + sizeof(macho_segment_command<P>)); const macho_section<P>* const sectionsEnd = §ionsStart[segCmd->nsects()]; for (const macho_section<P>* sect = sectionsStart; sect < sectionsEnd; ++sect) { ++sectionIndex; if ( strcmp(sect->sectname(), "__text") == 0 ) { _textSection = sect; _textSectionIndex = sectionIndex; } else if ( ((sect->flags() & SECTION_TYPE) == S_SYMBOL_STUBS) && (sect->size() != 0) ) { _stubSection = sect; _stubSectionIndex = sectionIndex; } } } break; } cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize()); } } template <typename P> uint32_t StubOptimizer<P>::lazyPointerAddrFromArmStub(const uint8_t* stubInstructions, uint32_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions+4)); uint32_t stubInstr3 = E::get32(*(uint32_t*)(stubInstructions+8)); int32_t stubData = E::get32(*(uint32_t*)(stubInstructions+12)); if ( stubInstr1 != 0xe59fc004 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not 'ldr ip, pc + 12' for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } if ( stubInstr2 != 0xe08fc00c ) { _diagnostics.warning("second instruction of stub (0x%08X) is not 'add ip, pc, ip' for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } if ( stubInstr3 != 0xe59cf000 ) { _diagnostics.warning("third instruction of stub (0x%08X) is not 'ldr pc, [ip]' for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } return stubVMAddr + 12 + stubData; } template <typename P> uint64_t StubOptimizer<P>::lazyPointerAddrFromArm64Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); if ( (stubInstr1 & 0x9F00001F) != 0x90000010 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not ADRP for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } int32_t adrpValue = ((stubInstr1 & 0x00FFFFE0) >> 3) | ((stubInstr1 & 0x60000000) >> 29); if ( stubInstr1 & 0x00800000 ) adrpValue |= 0xFFF00000; uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions + 4)); if ( (stubInstr2 & 0xFFC003FF) != 0xF9400210 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not LDR for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } uint32_t ldrValue = ((stubInstr2 >> 10) & 0x00000FFF); return (stubVMAddr & (-4096)) + adrpValue*4096 + ldrValue*8; } #if SUPPORT_ARCH_arm64_32 template <typename P> uint64_t StubOptimizer<P>::lazyPointerAddrFromArm64_32Stub(const uint8_t* stubInstructions, uint64_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); if ( (stubInstr1 & 0x9F00001F) != 0x90000010 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not ADRP for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } int32_t adrpValue = ((stubInstr1 & 0x00FFFFE0) >> 3) | ((stubInstr1 & 0x60000000) >> 29); if ( stubInstr1 & 0x00800000 ) adrpValue |= 0xFFF00000; uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions + 4)); if ( (stubInstr2 & 0xFFC003FF) != 0xB9400210 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not LDR for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } uint32_t ldrValue = ((stubInstr2 >> 10) & 0x00000FFF); return (stubVMAddr & (-4096)) + adrpValue*4096 + ldrValue*4; // LDR Wn has a scale factor of 4 } #endif #if SUPPORT_ARCH_arm64e template <typename P> uint64_t StubOptimizer<P>::lazyPointerAddrFromArm64eStub(const uint8_t* stubInstructions, uint64_t stubVMAddr) { uint32_t stubInstr1 = E::get32(*(uint32_t*)stubInstructions); // ADRP X17, dyld_ImageLoaderCache@page if ( (stubInstr1 & 0x9F00001F) != 0x90000011 ) { _diagnostics.warning("first instruction of stub (0x%08X) is not ADRP for stub at addr 0x%0llX in %s", stubInstr1, (uint64_t)stubVMAddr, _dylibID); return 0; } int32_t adrpValue = ((stubInstr1 & 0x00FFFFE0) >> 3) | ((stubInstr1 & 0x60000000) >> 29); if ( stubInstr1 & 0x00800000 ) adrpValue |= 0xFFF00000; // ADD X17, X17, dyld_ImageLoaderCache@pageoff uint32_t stubInstr2 = E::get32(*(uint32_t*)(stubInstructions + 4)); if ( (stubInstr2 & 0xFFC003FF) != 0x91000231 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not ADD for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } uint32_t addValue = ((stubInstr2 & 0x003FFC00) >> 10); // LDR X16, [X17] uint32_t stubInstr3 = E::get32(*(uint32_t*)(stubInstructions + 8)); if ( stubInstr3 != 0xF9400230 ) { _diagnostics.warning("second instruction of stub (0x%08X) is not LDR for stub at addr 0x%0llX in %s", stubInstr2, (uint64_t)stubVMAddr, _dylibID); return 0; } return (stubVMAddr & (-4096)) + adrpValue*4096 + addValue; } #endif template <typename P> void StubOptimizer<P>::buildStubMap(const std::unordered_set<std::string>& neverStubEliminate) { // find all stubs and lazy pointers const macho_nlist<P>* symbolTable = (const macho_nlist<P>*)(&_linkeditBias[_symTabCmd->symoff()]); const char* symbolStrings = (char*)(&_linkeditBias[_symTabCmd->stroff()]); const uint32_t* const indirectTable = (uint32_t*)(&_linkeditBias[_dynSymTabCmd->indirectsymoff()]); const macho_load_command<P>* const cmds = (macho_load_command<P>*)((uint8_t*)_mh + sizeof(macho_header<P>)); const uint32_t cmd_count = _mh->ncmds(); const macho_load_command<P>* cmd = cmds; for (uint32_t i = 0; i < cmd_count; ++i) { if ( cmd->cmd() == macho_segment_command<P>::CMD ) { macho_segment_command<P>* seg = (macho_segment_command<P>*)cmd; macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)seg + sizeof(macho_segment_command<P>)); macho_section<P>* const sectionsEnd = §ionsStart[seg->nsects()]; for(macho_section<P>* sect = sectionsStart; sect < sectionsEnd; ++sect) { if ( sect->size() == 0 ) continue; unsigned sectionType = (sect->flags() & SECTION_TYPE); const uint32_t indirectTableOffset = sect->reserved1(); if ( sectionType == S_SYMBOL_STUBS ) { const uint32_t stubSize = sect->reserved2(); _stubCount = (uint32_t)(sect->size() / stubSize); pint_t stubVMAddr = (pint_t)sect->addr(); for (uint32_t j=0; j < _stubCount; ++j, stubVMAddr += stubSize) { uint32_t symbolIndex = E::get32(indirectTable[indirectTableOffset + j]); switch ( symbolIndex ) { case INDIRECT_SYMBOL_ABS: case INDIRECT_SYMBOL_LOCAL: case INDIRECT_SYMBOL_ABS | INDIRECT_SYMBOL_LOCAL: break; default: if ( symbolIndex >= _symTabCmd->nsyms() ) { _diagnostics.warning("symbol index out of range (%d of %d) for stub at addr 0x%0llX in %s", symbolIndex, _symTabCmd->nsyms(), (uint64_t)stubVMAddr, _dylibID); continue; } const macho_nlist<P>* sym = &symbolTable[symbolIndex]; uint32_t stringOffset = sym->n_strx(); if ( stringOffset > _symTabCmd->strsize() ) { _diagnostics.warning("symbol string offset out of range (%u of %u) for stub at addr 0x%0llX in %s", stringOffset, sym->n_strx(), (uint64_t)stubVMAddr, _dylibID); continue; } const char* symName = &symbolStrings[stringOffset]; if ( neverStubEliminate.count(symName) ) { //fprintf(stderr, "stubVMAddr=0x%llX, not bypassing stub to %s in %s because target is interposable\n", (uint64_t)stubVMAddr, symName, _dylibID); _stubsLeftInterposable++; continue; } const uint8_t* stubInstrs = (uint8_t*)(long)stubVMAddr + _cacheSlide; pint_t targetLPAddr = 0; switch ( _mh->cputype() ) { case CPU_TYPE_ARM64: #if SUPPORT_ARCH_arm64e if (cpuSubtype() == CPU_SUBTYPE_ARM64E) targetLPAddr = (pint_t)lazyPointerAddrFromArm64eStub(stubInstrs, stubVMAddr); else #endif targetLPAddr = (pint_t)lazyPointerAddrFromArm64Stub(stubInstrs, stubVMAddr); break; #if SUPPORT_ARCH_arm64_32 case CPU_TYPE_ARM64_32: if (cpuSubtype() == CPU_SUBTYPE_ARM64_32_V8) targetLPAddr = (pint_t)lazyPointerAddrFromArm64_32Stub(stubInstrs, stubVMAddr); break; #endif case CPU_TYPE_ARM: targetLPAddr = (pint_t)lazyPointerAddrFromArmStub(stubInstrs, (uint32_t)stubVMAddr); break; } if ( targetLPAddr != 0 ) _stubAddrToLPAddr[stubVMAddr] = targetLPAddr; break; } } } else if ( (sectionType == S_LAZY_SYMBOL_POINTERS) || (sectionType == S_NON_LAZY_SYMBOL_POINTERS) ) { pint_t lpVMAddr; pint_t* lpContent = (pint_t*)(sect->addr() + _cacheSlide); uint32_t elementCount = (uint32_t)(sect->size() / sizeof(pint_t)); uint64_t textSegStartAddr = _segCmds[0]->vmaddr(); uint64_t textSegEndAddr = _segCmds[0]->vmaddr() + _segCmds[0]->vmsize(); pint_t lpValue; const CacheBuilder::DylibSectionCoalescer::OptimizedSection* optimizedSection = nullptr; if ( !strcmp(sect->sectname(), "__got") ) optimizedSection = this->_coalescedGOTs; else if ( !strcmp(sect->sectname(), "__auth_got") ) optimizedSection = this->_coalescedAuthGOTs; for (uint32_t j=0; j < elementCount; ++j) { uint32_t symbolIndex = E::get32(indirectTable[indirectTableOffset + j]); switch ( symbolIndex ) { case INDIRECT_SYMBOL_ABS: case INDIRECT_SYMBOL_LOCAL: case INDIRECT_SYMBOL_LOCAL|INDIRECT_SYMBOL_ABS: break; default: lpValue = (pint_t)P::getP(lpContent[j]); lpVMAddr = (pint_t)sect->addr() + j * sizeof(pint_t); if ( symbolIndex >= _symTabCmd->nsyms() ) { _diagnostics.warning("symbol index out of range (%d of %d) for lazy pointer at addr 0x%0llX in %s", symbolIndex, _symTabCmd->nsyms(), (uint64_t)lpVMAddr, _dylibID); continue; } const macho_nlist<P>* sym = &symbolTable[symbolIndex]; uint32_t stringOffset = sym->n_strx(); if ( stringOffset > _symTabCmd->strsize() ) { _diagnostics.warning("symbol string offset out of range (%u of %u) for lazy pointer at addr 0x%0llX in %s", stringOffset, sym->n_strx(), (uint64_t)lpVMAddr, _dylibID); continue; } const char* symName = &symbolStrings[stringOffset]; // GOT uniquing redirected the stub to a new GOT, so it won't point to this one // Additionally, this GOT has been set to null, so that any accidental uses would be crashes // If this is a rewritten GOT, change it to point to the new GOT if ( optimizedSection != nullptr ) { uint32_t sectionOffset = (uint32_t)(j * sizeof(pint_t)); auto it = optimizedSection->offsetMap.find(sectionOffset); if ( it != optimizedSection->offsetMap.end() ) { uint64_t cacheGOTVMAddr = optimizedSection->subCacheSection->bufferVMAddr + it->second; lpVMAddr = (pint_t)cacheGOTVMAddr; // Load the GOT in the cache to see where points to const uint8_t* cacheGOTLocation = optimizedSection->subCacheSection->bufferAddr + it->second; lpValue = (pint_t)P::getP(*(pint_t*)cacheGOTLocation); } } if ( (lpValue > textSegStartAddr) && (lpValue< textSegEndAddr) ) { //fprintf(stderr, "skipping lazy pointer at 0x%0lX to %s in %s because target is within dylib\n", (long)lpVMAddr, symName, _dylibID); } else if ( (sizeof(pint_t) == 8) && ((lpValue % 4) != 0) ) { // Only warn on lazy pointers which correspond to call targets if ( sectionType == S_LAZY_SYMBOL_POINTERS ) { _diagnostics.warning("lazy pointer at 0x%0llX does not point to 4-byte aligned address(0x%0llX) for symbol '%s' in %s", (uint64_t)lpVMAddr, (uint64_t)lpValue, symName, _dylibID); } } else { _lpAddrToTargetAddr[lpVMAddr] = lpValue; _targetAddrToName[lpValue] = symName; } break; } } } } } cmd = (const macho_load_command<P>*)(((uint8_t*)cmd)+cmd->cmdsize()); } } template <typename P> void StubOptimizer<P>::forEachCallSiteToAStub(CallSiteHandler handler) { if (_diagnostics.hasError()) return; const uint8_t* infoStart = &_linkeditBias[_splitSegInfoCmd->dataoff()]; const uint8_t* infoEnd = &infoStart[_splitSegInfoCmd->datasize()]; if ( *infoStart++ != DYLD_CACHE_ADJ_V2_FORMAT ) { _diagnostics.error("malformed split seg info in %s", _dylibID); return; } uint8_t* textSectionContent = (uint8_t*)(_textSection->addr() + _cacheSlide); // Whole :== <count> FromToSection+ // FromToSection :== <from-sect-index> <to-sect-index> <count> ToOffset+ // ToOffset :== <to-sect-offset-delta> <count> FromOffset+ // FromOffset :== <kind> <count> <from-sect-offset-delta> const uint8_t* p = infoStart; uint64_t sectionCount = read_uleb128(p, infoEnd); for (uint64_t i=0; i < sectionCount; ++i) { uint64_t fromSectionIndex = read_uleb128(p, infoEnd); uint64_t toSectionIndex = read_uleb128(p, infoEnd); uint64_t toOffsetCount = read_uleb128(p, infoEnd); uint64_t toSectionOffset = 0; for (uint64_t j=0; j < toOffsetCount; ++j) { uint64_t toSectionDelta = read_uleb128(p, infoEnd); uint64_t fromOffsetCount = read_uleb128(p, infoEnd); toSectionOffset += toSectionDelta; for (uint64_t k=0; k < fromOffsetCount; ++k) { uint64_t kind = read_uleb128(p, infoEnd); if ( kind > 13 ) { _diagnostics.error("bad kind (%llu) value in %s\n", kind, _dylibID); } uint64_t fromSectDeltaCount = read_uleb128(p, infoEnd); uint64_t fromSectionOffset = 0; for (uint64_t l=0; l < fromSectDeltaCount; ++l) { uint64_t delta = read_uleb128(p, infoEnd); fromSectionOffset += delta; if ( (fromSectionIndex == _textSectionIndex) && (toSectionIndex == _stubSectionIndex) ) { uint32_t* instrPtr = (uint32_t*)(textSectionContent + fromSectionOffset); uint64_t instrAddr = _textSection->addr() + fromSectionOffset; uint64_t stubAddr = _stubSection->addr() + toSectionOffset; uint32_t instruction = E::get32(*instrPtr); _branchToStubCount++; if ( handler(kind, instrAddr, stubAddr, instruction) ) { E::set32(*instrPtr, instruction); } } } } } } } /// Extract displacement from a thumb b/bl/blx instruction. template <typename P> int32_t StubOptimizer<P>::getDisplacementFromThumbBranch(uint32_t instruction, uint32_t instrAddr) { bool is_blx = ((instruction & 0xD000F800) == 0xC000F000); uint32_t s = (instruction >> 10) & 0x1; uint32_t j1 = (instruction >> 29) & 0x1; uint32_t j2 = (instruction >> 27) & 0x1; uint32_t imm10 = instruction & 0x3FF; uint32_t imm11 = (instruction >> 16) & 0x7FF; uint32_t i1 = (j1 == s); uint32_t i2 = (j2 == s); uint32_t dis = (s << 24) | (i1 << 23) | (i2 << 22) | (imm10 << 12) | (imm11 << 1); int32_t sdis = dis; int32_t result = s ? (sdis | 0xFE000000) : sdis; if ( is_blx && (instrAddr & 0x2) ) { // The thumb blx instruction always has low bit of imm11 as zero. The way // a 2-byte aligned blx can branch to a 4-byte aligned ARM target is that // the blx instruction always 4-byte aligns the pc before adding the // displacement from the blx. We must emulate that when decoding this. result -= 2; } return result; } /// Update a thumb b/bl/blx instruction, switching bl <-> blx as needed. template <typename P> uint32_t StubOptimizer<P>::setDisplacementInThumbBranch(uint32_t instruction, uint32_t instrAddr, int32_t displacement, bool targetIsThumb) { if ( (displacement > 16777214) || (displacement < (-16777216)) ) { _diagnostics.error("thumb branch out of range at 0x%0X in %s", instrAddr, _dylibID); return 0; } bool is_bl = ((instruction & 0xD000F800) == 0xD000F000); bool is_blx = ((instruction & 0xD000F800) == 0xC000F000); bool is_b = ((instruction & 0xD000F800) == 0x9000F000); uint32_t newInstruction = (instruction & 0xD000F800); if (is_bl || is_blx) { if (targetIsThumb) { newInstruction = 0xD000F000; // Use bl } else { newInstruction = 0xC000F000; // Use blx // See note in getDisplacementFromThumbBranch() about blx. if (instrAddr & 0x2) displacement += 2; } } else if (is_b) { if ( !targetIsThumb ) { _diagnostics.error("no pc-rel thumb branch instruction that switches to arm mode at 0x%0X in %s", instrAddr, _dylibID); return 0; } } else { _diagnostics.error("not b/bl/blx at 0x%0X in %s", instrAddr, _dylibID); return 0; } uint32_t s = (uint32_t)(displacement >> 24) & 0x1; uint32_t i1 = (uint32_t)(displacement >> 23) & 0x1; uint32_t i2 = (uint32_t)(displacement >> 22) & 0x1; uint32_t imm10 = (uint32_t)(displacement >> 12) & 0x3FF; uint32_t imm11 = (uint32_t)(displacement >> 1) & 0x7FF; uint32_t j1 = (i1 == s); uint32_t j2 = (i2 == s); uint32_t nextDisp = (j1 << 13) | (j2 << 11) | imm11; uint32_t firstDisp = (s << 10) | imm10; newInstruction |= (nextDisp << 16) | firstDisp; return newInstruction; } template <typename P> void StubOptimizer<P>::optimizeArmCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr) { forEachCallSiteToAStub([&](uint8_t kind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction) -> bool { if ( kind == DYLD_CACHE_ADJ_V2_THUMB_BR22 ) { bool is_bl = ((instruction & 0xD000F800) == 0xD000F000); bool is_blx = ((instruction & 0xD000F800) == 0xC000F000); bool is_b = ((instruction & 0xD000F800) == 0x9000F000); if ( !is_bl && !is_blx && !is_b ){ _diagnostics.warning("non-branch instruction at 0x%0llX in %s", callSiteAddr, _dylibID); return false; } int32_t brDelta = getDisplacementFromThumbBranch(instruction, (uint32_t)callSiteAddr); pint_t targetAddr = (pint_t)callSiteAddr + 4 + brDelta; if ( targetAddr != stubAddr ) { _diagnostics.warning("stub target mismatch at callsite 0x%0llX in %s", callSiteAddr, _dylibID); return false; } // ignore branch if not to a known stub const auto& pos = _stubAddrToLPAddr.find(targetAddr); if ( pos == _stubAddrToLPAddr.end() ) return false; // ignore branch if lazy pointer is not known (resolver or interposable) uint64_t lpAddr = pos->second; const auto& pos2 = _lpAddrToTargetAddr.find((pint_t)lpAddr); if ( pos2 == _lpAddrToTargetAddr.end() ) return false; uint64_t finalTargetAddr = pos2->second; int64_t deltaToFinalTarget = finalTargetAddr - (callSiteAddr + 4); // if final target within range, change to branch there directly if ( (deltaToFinalTarget > -b16MegLimit) && (deltaToFinalTarget < b16MegLimit) ) { bool targetIsThumb = (finalTargetAddr & 1); instruction = setDisplacementInThumbBranch(instruction, (uint32_t)callSiteAddr, (int32_t)deltaToFinalTarget, targetIsThumb); if (_diagnostics.hasError()) return false; _branchOptimizedToDirectCount++; return true; } // try to re-use an existing optimized stub const auto& pos3 = targetAddrToOptStubAddr.find(finalTargetAddr); if ( pos3 != targetAddrToOptStubAddr.end() ) { uint64_t existingStub = pos3->second; if ( existingStub != stubAddr ) { int64_t deltaToOptStub = existingStub - (callSiteAddr + 4); if ( (deltaToOptStub > -b16MegLimit) && (deltaToOptStub < b16MegLimit) ) { bool targetIsThumb = (existingStub & 1); instruction = setDisplacementInThumbBranch(instruction, (uint32_t)callSiteAddr, (int32_t)deltaToOptStub, targetIsThumb); if (_diagnostics.hasError()) return false; _branchToReUsedOptimizedStubCount++; return true; } } } // leave as BL to stub, but optimize the stub _stubsToOptimize.insert(stubAddr); targetAddrToOptStubAddr[finalTargetAddr] = stubAddr; _branchToOptimizedStubCount++; return false; } else if ( kind == DYLD_CACHE_ADJ_V2_ARM_BR24 ) { // too few of these to be worth trying to optimize } return false; }); if (_diagnostics.hasError()) return; } template <typename P> void StubOptimizer<P>::optimizeArmStubs() { for (const auto& stubEntry : _stubAddrToLPAddr) { pint_t stubVMAddr = stubEntry.first; pint_t lpVMAddr = stubEntry.second; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int32_t delta = (int32_t)(targetVMAddr - (stubVMAddr + 12)); uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); assert(stubInstructions[0] == 0xe59fc004); stubInstructions[0] = 0xe59fc000; // ldr ip, L0 stubInstructions[1] = 0xe08ff00c; // add pc, pc, ip stubInstructions[2] = delta; // L0: .long xxxx stubInstructions[3] = 0xe7ffdefe; // trap _stubOptimizedCount++; } } template <typename P> void StubOptimizer<P>::optimizeArm64Stubs() { for (const uint64_t stubVMAddr : _stubsToOptimize ) { pint_t lpVMAddr = _stubAddrToLPAddr[(pint_t)stubVMAddr]; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int64_t adrpDelta = (targetVMAddr & -4096) - (stubVMAddr & -4096); // Note: ADRP/ADD can only span +/-4GB uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); bool rightInstr1 = ((stubInstructions[0] & 0x9F00001F) == 0x90000010); // ADRP X16, lp@page bool rightInstr2 = ((stubInstructions[1] & 0xFFC003FF) == 0xF9400210); // LDR X16, [X16, lp@pageoff] bool rightInstr3 = (stubInstructions[2] == 0xD61F0200); // BR X16 if ( rightInstr1 && rightInstr2 && rightInstr3 ) { uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (targetVMAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 _stubOptimizedCount++; } } } #if SUPPORT_ARCH_arm64e template <typename P> void StubOptimizer<P>::optimizeArm64eStubs() { for (const uint64_t stubVMAddr : _stubsToOptimize ) { pint_t lpVMAddr = _stubAddrToLPAddr[(pint_t)stubVMAddr]; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int64_t adrpDelta = (targetVMAddr & -4096) - (stubVMAddr & -4096); // Note: ADRP/ADD can only span +/-4GB uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); bool rightInstr1 = ((stubInstructions[0] & 0x9F00001F) == 0x90000011); // ADRP X17, lp@page bool rightInstr2 = ((stubInstructions[1] & 0xFFC003FF) == 0x91000231); // ADD X17, [X17, lp@pageoff] bool rightInstr3 = (stubInstructions[2] == 0xF9400230); // LDR X16, [X17] bool rightInstr4 = (stubInstructions[3] == 0xD71F0A11); // BRAA X16, X17 if ( rightInstr1 && rightInstr2 && rightInstr3 && rightInstr4) { uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (targetVMAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 stubInstructions[3] = 0xD4200020; // TRAP _stubOptimizedCount++; } } } #endif #if SUPPORT_ARCH_arm64_32 template <typename P> void StubOptimizer<P>::optimizeArm64_32Stubs() { for (const uint64_t stubVMAddr : _stubsToOptimize ) { pint_t lpVMAddr = _stubAddrToLPAddr[(pint_t)stubVMAddr]; const auto& pos = _lpAddrToTargetAddr.find(lpVMAddr); if ( pos == _lpAddrToTargetAddr.end() ) return; pint_t targetVMAddr = pos->second; int64_t adrpDelta = (targetVMAddr & -4096) - (stubVMAddr & -4096); uint32_t* stubInstructions = (uint32_t*)((uint8_t*)(long)stubVMAddr + _cacheSlide); bool rightInstr1 = ((stubInstructions[0] & 0x9F00001F) == 0x90000010); // ADRP X16, lp@page bool rightInstr2 = ((stubInstructions[1] & 0xFFC003FF) == 0xB9400210); // LDR W16, [X16, lp@pageoff] bool rightInstr3 = (stubInstructions[2] == 0xD61F0200); // BR X16 if ( rightInstr1 && rightInstr2 && rightInstr3 ) { uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (targetVMAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 _stubOptimizedCount++; } } } #endif template <typename P> void StubOptimizer<P>::optimizeArm64CallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr) { forEachCallSiteToAStub([&](uint8_t kind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction) -> bool { if ( kind != DYLD_CACHE_ADJ_V2_ARM64_BR26 ) return false; // skip all but BL or B if ( (instruction & 0x7C000000) != 0x14000000 ) return false; // compute target of branch instruction int32_t brDelta = (instruction & 0x03FFFFFF) << 2; if ( brDelta & 0x08000000 ) brDelta |= 0xF0000000; uint64_t targetAddr = callSiteAddr + (int64_t)brDelta; if ( targetAddr != stubAddr ) { _diagnostics.warning("stub target mismatch"); return false; } // ignore branch if not to a known stub const auto& pos = _stubAddrToLPAddr.find((pint_t)targetAddr); if ( pos == _stubAddrToLPAddr.end() ) return false; // ignore branch if lazy pointer is not known (resolver or interposable) uint64_t lpAddr = pos->second; const auto& pos2 = _lpAddrToTargetAddr.find((pint_t)lpAddr); if ( pos2 == _lpAddrToTargetAddr.end() ) return false; uint64_t finalTargetAddr = pos2->second; int64_t deltaToFinalTarget = finalTargetAddr - callSiteAddr; // if final target within range, change to branch there directly if ( (deltaToFinalTarget > -b128MegLimit) && (deltaToFinalTarget < b128MegLimit) ) { instruction= (instruction & 0xFC000000) | ((deltaToFinalTarget >> 2) & 0x03FFFFFF); _branchOptimizedToDirectCount++; return true; } // try to re-use an existing optimized stub const auto& pos3 = targetAddrToOptStubAddr.find((pint_t)finalTargetAddr); if ( pos3 != targetAddrToOptStubAddr.end() ) { uint64_t existingStub = pos3->second; if ( existingStub != stubAddr ) { int64_t deltaToOptStub = existingStub - callSiteAddr; if ( (deltaToOptStub > -b128MegLimit) && (deltaToOptStub < b128MegLimit) ) { instruction = (instruction & 0xFC000000) | ((deltaToOptStub >> 2) & 0x03FFFFFF); _branchToReUsedOptimizedStubCount++; return true; } } } // leave as BL to stub, but optimize the stub _stubsToOptimize.insert(stubAddr); targetAddrToOptStubAddr[(pint_t)finalTargetAddr] = (pint_t)stubAddr; _branchToOptimizedStubCount++; return false; }); if (_diagnostics.hasError()) return; } template <typename P> void StubOptimizer<P>::redirectArm64_32CallSitesToIslands() { forEachCallSiteToAStub([&](uint8_t kind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction) -> bool { if ( kind != DYLD_CACHE_ADJ_V2_ARM64_BR26 ) return false; // skip all but BL or B if ( (instruction & 0x7C000000) != 0x14000000 ) return false; // compute target of branch instruction int32_t brDelta = (instruction & 0x03FFFFFF) << 2; if ( brDelta & 0x08000000 ) brDelta |= 0xF0000000; uint64_t targetAddr = callSiteAddr + (int64_t)brDelta; if ( targetAddr != stubAddr ) { _diagnostics.warning("stub target mismatch"); return false; } // ignore branch if not to a known stub const auto& pos = _stubAddrToLPAddr.find((pint_t)targetAddr); if ( pos == _stubAddrToLPAddr.end() ) return false; uint64_t lpAddr = pos->second; // ignore branch if lazy pointer is not known (resolver or interposable) const auto& posB = _lpAddrToTargetAddr.find((pint_t)lpAddr); if ( posB == _lpAddrToTargetAddr.end() ) { return false; } uint64_t finalTargetAddr = posB->second; // change BL target to stub island const auto& posC = _stubsToIslands.find(stubAddr); if ( posC == _stubsToIslands.end() ) { _diagnostics.error("could not find stub in islands"); return false; } uint64_t newStubAddr = posC->second.first; uint8_t* devStubsBuffer = posC->second.second; int64_t deltaToNewStub = newStubAddr - callSiteAddr; if ( (deltaToNewStub <= -b128MegLimit) || (deltaToNewStub >= b128MegLimit) ) { _diagnostics.error("%s call could not reach stub island at offset 0x%llx", this->dylibID(), deltaToNewStub); return false; } // customer int64_t adrpDelta = (finalTargetAddr & -4096) - ((uint64_t)newStubAddr & -4096); uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (finalTargetAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); uint32_t* stubInstructions = (uint32_t*)(newStubAddr + _cacheSlide); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 // dev adrpDelta = (lpAddr & -4096) - ((uint64_t)newStubAddr & -4096); immhi = (adrpDelta >> 9) & (0x00FFFFE0); immlo = (adrpDelta << 17) & (0x60000000); newADRP = (0x90000010) | immlo | immhi; off12 = (lpAddr & 0xFFF) >> 2; uint32_t newLDR = (0xB9400210) | (off12 << 10); stubInstructions = (uint32_t*)devStubsBuffer; stubInstructions[0] = newADRP; // ADRP X16, lazy_pointer@page stubInstructions[1] = newLDR; // LDR W16, [X16, lazy_pointer@pageoff] stubInstructions[2] = 0xD61F0200; // BR X16 return true; }); } template <typename P> void StubOptimizer<P>::redirectArm64CallSitesToIslands() { forEachCallSiteToAStub([&](uint8_t kind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction) -> bool { if ( kind != DYLD_CACHE_ADJ_V2_ARM64_BR26 ) return false; // skip all but BL or B if ( (instruction & 0x7C000000) != 0x14000000 ) return false; // compute target of branch instruction int32_t brDelta = (instruction & 0x03FFFFFF) << 2; if ( brDelta & 0x08000000 ) brDelta |= 0xF0000000; uint64_t targetAddr = callSiteAddr + (int64_t)brDelta; if ( targetAddr != stubAddr ) { _diagnostics.warning("stub target mismatch"); return false; } // ignore branch if not to a known stub const auto& pos = _stubAddrToLPAddr.find((pint_t)targetAddr); if ( pos == _stubAddrToLPAddr.end() ) return false; uint64_t lpAddr = pos->second; // ignore branch if lazy pointer is not known (resolver or interposable) const auto& posB = _lpAddrToTargetAddr.find((pint_t)lpAddr); if ( posB == _lpAddrToTargetAddr.end() ) { return false; } uint64_t finalTargetAddr = posB->second; // change BL target to stub island const auto& posC = _stubsToIslands.find(stubAddr); if ( posC == _stubsToIslands.end() ) { _diagnostics.error("could not find stub in islands"); return false; } uint64_t newStubAddr = posC->second.first; uint8_t* devStubsBuffer = posC->second.second; int64_t deltaToNewStub = newStubAddr - callSiteAddr; if ( (deltaToNewStub <= -b128MegLimit) || (deltaToNewStub >= b128MegLimit) ) { _diagnostics.error("%s call could not reach stub island at offset 0x%llx", this->dylibID(), deltaToNewStub); return false; } // customer int64_t adrpDelta = (finalTargetAddr & -4096) - ((uint64_t)newStubAddr & -4096); uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (finalTargetAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); uint32_t* stubInstructions = (uint32_t*)(newStubAddr + _cacheSlide); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 // dev adrpDelta = (lpAddr & -4096) - ((uint64_t)newStubAddr & -4096); immhi = (adrpDelta >> 9) & (0x00FFFFE0); immlo = (adrpDelta << 17) & (0x60000000); newADRP = (0x90000010) | immlo | immhi; off12 = (lpAddr & 0xFFF); uint32_t newLDR = (0xF9400210) | (off12 << 10); stubInstructions = (uint32_t*)devStubsBuffer; stubInstructions[0] = newADRP; // ADRP X16, lazy_pointer@page stubInstructions[1] = newLDR; // LDR X16, [X16, lazy_pointer@pageoff] stubInstructions[2] = 0xD61F0200; // BR X16 return true; }); } #if SUPPORT_ARCH_arm64e template <typename P> void StubOptimizer<P>::redirectArm64eCallSitesToIslands() { forEachCallSiteToAStub([&](uint8_t kind, uint64_t callSiteAddr, uint64_t stubAddr, uint32_t& instruction) -> bool { if ( kind != DYLD_CACHE_ADJ_V2_ARM64_BR26 ) return false; // skip all but BL or B if ( (instruction & 0x7C000000) != 0x14000000 ) return false; // compute target of branch instruction int32_t brDelta = (instruction & 0x03FFFFFF) << 2; if ( brDelta & 0x08000000 ) brDelta |= 0xF0000000; uint64_t targetAddr = callSiteAddr + (int64_t)brDelta; if ( targetAddr != stubAddr ) { _diagnostics.warning("stub target mismatch"); return false; } // ignore branch if not to a known stub const auto& pos = _stubAddrToLPAddr.find((pint_t)targetAddr); if ( pos == _stubAddrToLPAddr.end() ) return false; uint64_t lpAddr = pos->second; // ignore branch if lazy pointer is not known (resolver or interposable) const auto& posB = _lpAddrToTargetAddr.find((pint_t)lpAddr); if ( posB == _lpAddrToTargetAddr.end() ) { return false; } uint64_t finalTargetAddr = posB->second; // change BL target to stub island const auto& posC = _stubsToIslands.find(stubAddr); if ( posC == _stubsToIslands.end() ) { _diagnostics.error("could not find stub in islands"); return false; } uint64_t newStubAddr = posC->second.first; uint8_t* devStubsBuffer = posC->second.second; int64_t deltaToNewStub = newStubAddr - callSiteAddr; if ( (deltaToNewStub <= -b128MegLimit) || (deltaToNewStub >= b128MegLimit) ) { _diagnostics.error("%s call could not reach stub island at offset 0x%llx", this->dylibID(), deltaToNewStub); return false; } int64_t adrpDelta = (finalTargetAddr & -4096) - ((uint64_t)newStubAddr & -4096); uint32_t immhi = (adrpDelta >> 9) & (0x00FFFFE0); uint32_t immlo = (adrpDelta << 17) & (0x60000000); uint32_t newADRP = (0x90000010) | immlo | immhi; uint32_t off12 = (finalTargetAddr & 0xFFF); uint32_t newADD = (0x91000210) | (off12 << 10); uint32_t* stubInstructions = (uint32_t*)(newStubAddr + _cacheSlide); stubInstructions[0] = newADRP; // ADRP X16, target@page stubInstructions[1] = newADD; // ADD X16, X16, target@pageoff stubInstructions[2] = 0xD61F0200; // BR X16 stubInstructions[3] = 0xD4200020; // TRAP instruction = (instruction & 0xFC000000) | ((deltaToNewStub >> 2) & 0x03FFFFFF); // dev adrpDelta = (lpAddr & -4096) - ((uint64_t)newStubAddr & -4096); immhi = (adrpDelta >> 9) & (0x00FFFFE0); immlo = (adrpDelta << 17) & (0x60000000); newADRP = (0x90000011) | immlo | immhi; off12 = (lpAddr & 0xFFF); newADD = (0x91000231) | (off12 << 10); stubInstructions = (uint32_t*)devStubsBuffer; stubInstructions[0] = newADRP; // ADRP X17, lazy_pointer@page stubInstructions[1] = newADD; // ADD X17, X17, lazy_pointer@pageoff stubInstructions[2] = 0xF9400230; // LDR X16, [X17] stubInstructions[3] = 0xD71F0A11; // BRAA X16, X17 return true; }); } #endif template <typename P> void StubOptimizer<P>::redirectCallSitesToIslands() { if ( _textSection == NULL ) return; if ( _stubSection == NULL ) return; switch ( _mh->cputype() ) { case CPU_TYPE_ARM64: #if SUPPORT_ARCH_arm64e if (cpuSubtype() == CPU_SUBTYPE_ARM64E) redirectArm64eCallSitesToIslands(); else #endif redirectArm64CallSitesToIslands(); break; case CPU_TYPE_ARM64_32: redirectArm64_32CallSitesToIslands(); break; default: _diagnostics.error("stubs islands are unsupported for cpu type 0x%08X", _mh->cputype()); break; } } template <typename P> void StubOptimizer<P>::optimizeCallSites(std::unordered_map<uint64_t, uint64_t>& targetAddrToOptStubAddr) { if ( _textSection == NULL ) return; if ( _stubSection == NULL ) return; switch ( _mh->cputype() ) { case CPU_TYPE_ARM64: optimizeArm64CallSites(targetAddrToOptStubAddr); #if SUPPORT_ARCH_arm64e if (cpuSubtype() == CPU_SUBTYPE_ARM64E) optimizeArm64eStubs(); else #endif optimizeArm64Stubs(); break; #if SUPPORT_ARCH_arm64_32 case CPU_TYPE_ARM64_32: optimizeArm64CallSites(targetAddrToOptStubAddr); optimizeArm64_32Stubs(); break; #endif case CPU_TYPE_ARM: optimizeArmCallSites(targetAddrToOptStubAddr); optimizeArmStubs(); break; } if ( verbose ) { _diagnostics.verbose("dylib has %6u BLs to %4u stubs. Changed %5u, %5u, %5u BLs to use direct branch, optimized stub, neighbor's optimized stub. " "%5u stubs left interposable, %4u stubs optimized. path=%s\n", _branchToStubCount, _stubCount, _branchOptimizedToDirectCount, _branchToOptimizedStubCount, _branchToReUsedOptimizedStubCount, _stubsLeftInterposable, _stubOptimizedCount, _dylibID); } } template <typename P> void bypassStubs(std::vector<CacheBuilder::StubOptimizerInfo> images, const std::string& archName, int64_t cacheSlide, const DyldSharedCache* dyldCache, const std::unordered_map<uint64_t, std::pair<uint64_t, uint8_t*>>& stubsToIslands, const char* const neverStubEliminateSymbols[], Diagnostics& diags) { diags.verbose("Stub elimination optimization:\n"); // construct a StubOptimizer for each image __block std::vector<StubOptimizer<P>*> optimizers; for (const CacheBuilder::StubOptimizerInfo& image : images) { optimizers.push_back(new StubOptimizer<P>(cacheSlide, archName, image, stubsToIslands, diags)); } // build set of functions to never stub-eliminate because tools may need to override them std::unordered_set<std::string> neverStubEliminate; for (const char* const* p=neverStubEliminateSymbols; *p != nullptr; ++p) { neverStubEliminate.insert(*p); } #if !BUILDING_APP_CACHE_UTIL // Customer shared caches support overriding libdispatch if ( dyldCache != nullptr ) { for (StubOptimizer<P>* op : optimizers) { if ( dyldCache->isAlwaysOverridablePath(op->dylibID()) ) { // add all exports const uint8_t* exportsStart = op->exportsTrie(); const uint8_t* exportsEnd = exportsStart + op->exportsTrieSize(); if ( !stubsToIslands.empty() && op->exportsTrieSize() == 0) { // ignore errors if building multi-cache continue; } std::vector<ExportInfoTrie::Entry> exports; if ( !ExportInfoTrie::parseTrie(exportsStart, exportsEnd, exports) ) { diags.error("malformed exports trie in %s", op->dylibID()); return; } for(const ExportInfoTrie::Entry& entry : exports) { neverStubEliminate.insert(entry.name); } } } } #endif // build maps of stubs-to-lp and lp-to-target for (StubOptimizer<P>* op : optimizers) op->buildStubMap(neverStubEliminate); if ( !stubsToIslands.empty() ) { // rewrite call sites to point to stub islands for (StubOptimizer<P>* op : optimizers) op->redirectCallSitesToIslands(); } // optimize call sites to by-pass stubs or jump through island if ( stubsToIslands.empty() ) { std::unordered_map<uint64_t, uint64_t> targetAddrToOptStubAddr; for (StubOptimizer<P>* op : optimizers) op->optimizeCallSites(targetAddrToOptStubAddr); } // write total optimization info uint32_t callSiteCount = 0; uint32_t callSiteDirectOptCount = 0; for (StubOptimizer<P>* op : optimizers) { callSiteCount += op->_branchToStubCount; callSiteDirectOptCount += op->_branchOptimizedToDirectCount; } diags.verbose(" cache contains %u call sites of which %u were direct bound\n", callSiteCount, callSiteDirectOptCount); // clean up for (StubOptimizer<P>* op : optimizers) delete op; } void CacheBuilder::optimizeAwayStubs(const std::vector<StubOptimizerInfo>& images, int64_t cacheSlide, const DyldSharedCache* dyldCache, const std::unordered_map<uint64_t, std::pair<uint64_t, uint8_t*>>& stubsToIslands, const char* const neverStubEliminateSymbols[]) { std::string archName = _options.archs->name(); #if SUPPORT_ARCH_arm64_32 if ( startsWith(archName, "arm64_32") ) { bypassStubs<Pointer32<LittleEndian> >(images, archName, cacheSlide, dyldCache, stubsToIslands, neverStubEliminateSymbols, _diagnostics); return; } #endif if ( startsWith(archName, "arm64") ) { bypassStubs<Pointer64<LittleEndian> >(images, archName, cacheSlide, dyldCache, stubsToIslands, neverStubEliminateSymbols, _diagnostics); return; } if ( archName == "armv7k" ) { bypassStubs<Pointer32<LittleEndian> >(images, archName, cacheSlide, dyldCache, stubsToIslands, neverStubEliminateSymbols, _diagnostics); return; } // no stub optimization done for other arches } |